There are even windshield brackets made specifically for some phones, including Apple's iPhone and Motorola's Droid. (Just remember, in California the only legal spots to stick the device on windshields are in the lower left or right corners.)

Still, a dedicated GPS navigation device does have one advantage -- a bigger screen that's easier to read while driving. Also, they don't require a data subscription plan -- at least for basic functions -- to operate.

And prices of the car navigators are heading downward. Rubin said there probably would be several models available at the $100 level or less during the holiday shopping season.

For a bit more than that, you can get features that used to be exclusive to models that cost several hundred dollars. As an example, TomTom now has units available for about $130 that have lane assist, which used to be a premium item.

Here are some features to consider:

Street names: Voice instructions that include street names have become nearly standard. But if you can live without them, you might pick up a model at a deep discount.

Speed: It seems redundant, but a reading of your speed on the GPS screen is truly handy, especially if it also displays the speed limit on the road you're traveling.

Lane assist: Not a necessity, but extremely helpful at unfamiliar freeway interchanges. The screen shows which lane you should be in to stay on your route.

Traffic: Some units come with a free feature (there are also subscription pay versions) that warns of traffic tie-ups ahead. But this works only in some urban areas, generally picking up the information from local traffic agencies that broadcast the data.

In practice this is of limited use because it often doesn't give much warning before you're actually in the jam.

The feature will generally offer an alternative route to get around the traffic. But as we all know in Southern California, sometimes the alternative turns out to be even worse.